Longfin MakoIsurus paucus
Little is known about the life and habits of this slender relative of the shortfin mako and white shark. It has a pointed snout and notched, crescent shaped caudal (tail) fin, and is named for its decidedly long and rounded pectoral fins. It is dark blue-gray above and white below, and its large dorsal fins are also dark above and light below. Because of its poorer quality flesh, it isn't highly sought after by recreational or commercial fishers, but demand for shark meat and shark fins does bring quite a few of these sharks to market.
Order - Lamniformes
Family - Lamnidae
Genus - Isurus
Species - paucus
Common names used throughout the world include longfin mako (English), bake-aozame (Japanese), dientuso prieto (Spanish), långfenad mako (Swedish), langfinnet makohaj (Danish), langvin-mako (Afrikaans), langvinmakreelhaai (Dutch), makohai (German), marrajo carite (Spanish), ostronos dlugopletwy (Polish), petite taupe (French), tubarão (Creole, Portuguese), and tubarão- anequim-de-gadanha (Portuguese).
Importance to Humans
The meat of the longfin mako is utilized fresh, frozen, and dried or salted for human consumption, but the meat is of lower quality than that of the shortfin mako. The meat is also used for animal feed and fish meal. Fins are often removed from the rest of the shark at sea, and the carcass is thrown overboard. Valuable shark fins alone drive the commercial shark fishing industry. Shark fins are sought after to make shark fin soup, an Asian delicacy.
Danger to Humans
According to the International Shark Attack File, there have been no reported attacks by this species to humans, however it is potentially dangerous due to its large size and big teeth.
The conservation status of this species is uncertain. Problems for the longfin mako include the rarity of this shark in most places (except perhaps the western Atlantic Ocean); limited knowledge of its biology; large maximum size; apparently lower fecundity than the shortfin mako; and occurrence as a limited but complementary bycatch of high-intensity oceanic fisheries targeting shortfin makos, other sharks, and pelagic scombroid fishes. These problems should arouse the concern of conservation and fisheries organizations, because of increased mortality of an uncommon or rare species due to finning and possibly capture trauma. It is thought to have a very low, minimum population with a doubling time of more than 14 years.
The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
Geographical DistributionThe longfin mako is a circumtropical pelagic species recorded from the Indian Ocean, Pacific Ocean, and western north and eastern Atlantic Ocean. In the western Atlantic Ocean, the species is most common off the coast of Cuba, where it was first described, and in the straits of Florida. There are records of the longfin mako off of Florida, the Gulf Stream off eastern U.S., Cuba, and southern Brazil. In the eastern Atlantic Ocean, the species exists in Spain, Portugal, probably the Mediterranean, Morocco, western Sahara, Canary Islands, Mauritania, Guinea-bissau, Liberia, Ghana, and the Cape Verde Islands. It has also been recorded in the western Indian Ocean off of South Africa and Madagascar. In the western Pacific Ocean, the longfin mako has been found in Japan, Taiwan, and Australia. In the central Pacific, it has been recorded northeast of Micronesia, between Solomon and Nauru islands, the area south of Johnston and the Hawaiian islands, near Phoenix Island, and north of the Hawaiian Islands. Finally, in the eastern Pacific, it can be found off the coast of southern California.
The longfin mako is found in numerous localities off the northwestern African coast. The known distribution has been slightly broadening by recording the presence of the species in Iberian waters north of the 30th parallel. The abundance of the species in this area is not significant compared with that of the shortfin mako (Isurus oxyrhincus), but the presence of the species cannot be considered as accidental in the zone.
There is little known about the habitat of the longfin mako. It is thought to be an epipelagic shark, residing in both tropical and a warm temperate climates. It is common in the western Atlantic Ocean and possibly in the central Pacific Ocean, but it is rare elsewhere. It is thought to be deep dwelling, but depth data insufficient. The longfin mako is most likely a slow swimming and endothermic shark. As in other Lamnids, the longfin mako has counter current vascular heat exchangers for its body musculature, eyes, brain and viscera. This allows the animal to send heat to certain parts of the body when it is necessary, therefore the species can tolerate lower temperatures, which broadens its natural habitat.
1. Pectoral fins are as long or longer than head
2. Pectoral fins have broad tips
3. Caudal fin is lunate with single keel
4. Eyes are large
5. Teeth protrude from mouth
The longfin mako has a slender, spindle-shaped body with a moderately long conical snout and large blade-like teeth without lateral cusplets or serrations. Like other members of the family Lamnidae, the longfin mako has long gill slits for more efficient gas exchange.
The pectoral fins are broad-tipped and as long or longer than the head. The first dorsal fin is large with a light free rear tip. Both the anal fin and the second dorsal fin are quite small. There are strong keels on caudal peduncle and short secondary keels on caudal base. The caudal fin is crescent-shaped. The head of the longfin mako is conical and long in proportion to its total length, while the conical snout can vary from very acute to more or less blunt. The mouth shorter than it is wide with the lower teeth external. The eyes are large, round and lateral. The spiracles are minute and scarcely perceivable. The pectoral fins of the longfin mako are proportionately larger than those on the shortfin mako. The pectoral fins of the longfin mako are wide with a round tip, and they range between 22.5-30.7% of TL (nearly equal to the length of the head). The pelvic fins are short with concave posterior margins. The caudal fin is semilunate, and the upper lobe is not much larger than the lower one. The terminal caudal lobe is not prominent, and the subterminal notch is well distinguished.Similar species include: the shortfin mako (Isurus oxyrinchus), the blue shark (Prionace glauca), the white shark (Carcharodon carcharias), and the porbeagle (Lamna nasus). The longfin mako has proportionally longer fins than the shortfin mako and a larger eye. The blue shark lacks a strong caudal keel and a lunate caudal fin that are present in the longfin mako. The white shark has a snout that is less narrow and serrated triangular teeth. The porbeagle has small secondary caudal keels on its caudal fin. Also, the teeth of the porbeagle have lateral cusplets that are not present in the longfin mako.
The dorsolateral coloration is a dark slate-blue or gray-black in life, while the underside of the belly is white. However, the underside of the snout and jaw is dark in adults and large juveniles and it spreads to the origin of the pectoral fins, although not in young. The dark color of the flanks extends ventrally onto abdomen in adults. The top pelvic fins are completely dark, and the underside is white with a prominent dark margin. The first dorsal fin is also dark (as well as the anal fin), except for a white free rear tip and posterior margin. The limit between the blue and white colors on the caudal peduncle does not coincide with the margins of the expansions of the keels, but goes deeply onto the ventral surface. Changes in color are sudden and outlines are more or less irregular. Color is a taxonomic feature that is used but it is not conclusive to distinction between the different species.
The first teeth of the lower jaw are aligned in a continuous row with out remarkable external prominence. Teeth in upper jaw are similar to lower jaw. They have a wide base. They are monocuspid, meaning without secondary cusplets. The cusps are narrow and triangular. Teeth have both smooth and cutting edges, and he first anterior tooth has a complete cutting edge. The first two teeth are wider and straight. Compared to that of the shortfin mako, the third tooth of the longfin mako is more symmetrical and has straight edges. The longfin mako has 12 to 13 teeth on either side of its upper jaw and 11 to 13 teeth on either side of its lower jaw.
The denticles are densely distributed. The posterior margin is slightly "W" shaped. The denticles have 3 - 7 crests, and are ellipse-shaped with a longer vertical than horizontal width.
The maximum recorded length of the longfin mako is 13.7 ft. (417 cm); the size at birth is between 3.2 and 3.9 ft (97 and 120 cm). Adult males grow to 8.0 ft. (245 cm), while adult females grow from 8.0 to 13.7 ft (245 to 417 cm) long. A 7.2 foot (218 cm) specimen reportedly weighed 154 lbs (70 kg).
There is not much data on the food habits of the longfin mako, but it presumably feeds on schooling fishes and pelagic cephalopods.
The longfin mako is ovoviviparous. The fetuses of the longfin mako are larger than those of the shortfin mako. A type of intra-uterine cannibalism known as oviphagy (egg eating) may occur. Embryos that have hatched inside the female shark eat successive batches of unfertilized eggs. Therefore, only 1 pup is produced by each of the 2 uteri. Pups measure approximately 39 inches (100cm) in length at birth.
Larger sharks may feed upon juvenile longfin makos. Adult longfin makos likely fall prey only to humans.
There is no biological information available on common parasites of the longfin mako. It most likely shares parasites with other sharks in similar habitats.
The longfin mako was originally described as Isurus paucus in 1966 by Guitart Manday. It has a synonym of Isurus alatus, Garrick, 1967. The genus name, Isurus, is translated from the Greek "isos" meaning equal and "oura" meaning tail.
Prepared by: Trudy Wilson and Travis Ford